PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Environment, Controlled”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources

Living in a housing co-operative for low income women: issues of identity, environment and control.

The purpose of this study was to develop an understanding of how living on a low income affects the health of women and focused on the experiences of women living in a new housing co-operative built exclusively for unattached, low income women of middle age. Initially, the main focus of this study was the health beliefs, concerns, and practices of women living on a low income. As the study evolved, however, the experience of living in the housing co-operative was of such concern to the participants that the effects of housing on health came to have greater importance. A qualitative method was used based on Spradley's ethnographic method (Spradley, J. (1979). The ethnographic interview. Holt, Rinehart, and Winston, New York). Data included interviews with ten volunteer participants and field notes about these interviews and collection spanned a period of eight months. The major health issues that arose for the women focused around the concepts of the identity, environment and control. The women frequently mentioned aspects of the environment in regards to their health. The co-operative itself was an interesting environment with the potential to reduce the women's sense of isolation. The social context of the co-operative, however, was often cited as a source of stress rather than support. One of the most striking and unexpected findings of this study was that the women did not identify with one another. The women interviewed perceived themselves as a diverse group without a common identity. Finally, control emerged as a major theme underlining the women's perceptions of health. When asked to describe their lives, the women invariably began discussing coping strategies they used to manage on a low income. One woman actually made the connection between poverty and a lack of control by defining poverty as "having no options".

Adult↗

Chaotic dynamics of a behavior-based miniature mobile robot: effects of environment and control structure.

To study the regularity and complexity of autonomous behavior, the flow of sensory information obtained in autonomous mobile robots under various conditions was analyzed as a complex system. Sensory information time series Xn was collected from a miniature mobile robot during free navigation, and plotted on the return map, the graph of X(n+tau) vs. Xn. The plot exhibited a characteristic trajectory, representing the regularity of the time series. Correlation integral and Lyapunov exponent analysis also showed properties of deterministic chaos; the presence of fractal dimension and positive Lyapunov exponent. Analysis of sensory information obtained in the robot with three different neural controllers revealed that the autonomous robot behaves in such a way that the flow of sensory information is governed by a deterministic rule, and this pattern is unique to each controller. Furthermore, the analysis in various environments exhibited that transitions from one trajectory to another on the return map occur during the course of autonomous behavior. The fractal and Lyapunov dimensions calculated in various conditions indicate that these dimension could be utilized to quantify the complexity of autonomous behavior and the relative difficulty of tasks. Analyses at different evolutionary stage revealed that behavioral performance correlates with fractal dimension. These studies using a miniature mobile robot that allowed to idealize the experimental conditions demonstrated firmly that the complex analysis could be utilized in evaluation and optimization of autonomous systems and the behavior.

Behavior↗

Aquaculture of three phyla of marine invertebrates to yield bioactive metabolites: process developments and economics.

Large-scale, renewable supplies of chemical constituents derived from marine invertebrates have limited development of potential new natural product drugs. This paper describes the development of two in-sea aquaculture systems designed and engineered for production of large quantities of biomass for two species of marine invertebrates desired for their natural product chemical constituents. The two invertebrates and their products were: (1) the cosmopolitan, arborescent bryozoan Bugula neritina (Phylum Bryozoa) for its anticancer chemical constituent bryostatin 1; and (2) Ecteinascidia turbinate (Phylum Tunicata) the source of anticancer ecteinascidin 743. For the third invertebrate Phylum Porifera, and its representative sponge Acanthella cavernosa (desired for its anti-parasitic and anti-infective kalihinols) in-sea systems were not developed in favor of controlled environment tank aquaculture systems. For the bryozoan and tunicate, projected economics for commercial-scale in-sea production proved cost effective. This was in contrast to the controlled environment sponge culture tank system, which did not prove to be economical due to inherent slow growth and low natural product yields of the sponge in culture. A non-destructive method for "milking" natural product chemicals from sponges was tested and is described.

Animals↗

[Effectiveness evaluation and cost-effectiveness estimate for diarrhea control by environment improvement in rural area].

Diarrhea diseases had been controlled by improving water supplies and excreta disposal facility in Changge county, Henan. In 1983, the morbidity rate of diarrhea was 48% in trial village. After central water supply was established in 1986, the rate was decreased to 28.2%, and was further reduced to 11.08% by both improvement of water supplies toilets. In comparison with 1983, the reduction of the rate was 76.9%. The results showed that the two measures had a great impact on reduction of patients with diarrhea during the peak period from June to Oct. The patients below age four were three fourth reduced by improved water supply only. In comparison with control village, the morbidity rates of all age groups were reduced 54-79% by both improvement of water supplies and toilets. But there was no significant difference in the distribution of the pathogens. Both measures cost 46 Yuan per capita. The annual benefit of 23.5 Yuan per capita was obtained from reducing the diseases and saving working force and fertilizer. It was estimated that the total costs will be paid in 2 years and cost-benefit ratio will be 4.4 after 2 years.

Cost-Benefit Analysis↗

Uniformity of environmental conditions and plant growth in a hydroponic culture system for use in a growth room with aerial CO2 control.

A portable system of hydroponic culture was developed that maintained temperature, pH, and nutrient concentrations of circulating nutrient solutions. The hydroponic system is used within a controlled-environment room (CER) for control of aerial environment. The CER was equipped with an auto-calibrating system for atmospheric CO2 control. The control systems for the hydroponic chambers were able to maintain acidity within +/- 0.2 pH units and the temperature with +/- 0.5 degree C. Mixing time for the 200-liter volume of solution within a hydroponic chamber was less than 12 min. The CO2 control system was able to maintain aerial concentrations within +/- 10 ppm CO2 during the light period. The only gradient found to occur within the hydroponic chambers or CER was a slight gradient in aerial temperature along the length of hydroponic chambers. Growth of soybeans [Glycine max (L.) Merr.] was characterized during a 3-week period of vegetative development by leaf number and area, plant dry weight, total N content of plants, and N depletion from the nutrient solution. The growth characteristics among populations for three hydroponic chambers within the CER were not significantly different, and the percent standard errors of means of the measurements within populations from each chamber were nearly all less than 10%. Thus, the uniformity of plant growth reflected the uniformity of environmental conditions.

Atmosphere↗

Reducing crying and irritability in neonates using a continuously controlled early environment.

A mother's "holding" environment has been shown to be effective in reducing infant crying and irritability. When mothers hold or cuddle their infants they create a microenvironment with stimuli similar to those of the intrauterine environment. Several of these same stimuli were incorporated into a cradle designed to provide a similar "holding" environment for the infant when the mother was not there. Ninety healthy term newborn infants were randomized to an experimental (n = 45) or control group (n = 45). The experimental group used a cradle that produced motion, sound, tactile (containment), and reduced-light stimuli at stimulus levels that initially approximated intrauterine sensory stimulation levels and gradually decreased to the levels of the home environment over 16 weeks. The control group used an identical cradle with no stimulus modulation features. Infants were placed in their respective cradles from 2 hours after birth during the times they would normally be placed in an infant bed. The mother-infant interaction or parenting style was not changed or manipulated. Mothers' use of the cradles did not differ significantly. An electronic status monitor measured and recorded infant presence and crying in the cradles. The Brazelton Neonatal Behavioral Assessment Scale test was done at 1 to 2, 14, and 24 days of age by "blinded" examiners. Additionally, phone calls and home visits were conducted by a registered nurse.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Spectral quality and UV-B stress stimulate glycyrrhizin concentration of Glycyrrhiza uralensis in hydroponic and pot system.

Glycyrrhizin, the major bioactive component of Glycyrrhiza uralensis, is widely used as a natural sweetener. Recently glycyrrhizin has been shown to have anti-tumor activity, highly active in inhibiting replication of HIV-1 and SARS-associated virus and exhibits a number of pharmacological effects. The principle objective of the current study was to evaluate the effects of different spectral quality including red, blue, white and UV-B radiation on the production of glycyrrhizin, in a controlled environment. Plants were grown under artificial lights with elevated CO(2) concentration and both the pot and hydroponic plants were assigned to red and blue light treatments and those grown under white fluorescent lamps were used as control. In a separate experiment, pot plants were exposed to ultraviolet (UV)-B radiation (wavelength: 280-315 nm). The net photosynthetic rates (NPR) of the leaves reduced significantly immediately after exposure to the high intensity UV-B radiation (3 days at 1.13 W m(-2)). In case of the low intensity UV-B radiation (15 days at 0.43 W m(-2)), NPR was also reduced, but the rate of reduction was significantly slower than that of the high intensity treatment. The concentrations of glycyrrhizin quantified in the root tissues were highest in the plants grown under red light in both hydroponic and pot systems and the concentration increased linearly from 1- to 3-month-old pot plants. Both the low and high intensity of UV-B exposure increased the concentration of glycyrrhizin in the root tissues of 3-month-old pot plants, the values being nearly X1.5 those of the control. The results also indicate that the glycyrrhizin concentrations of 3-6 months old pot plants were similar or even higher than the previously reported values for 3-4 years old field-grown plants and confirm that high concentration of glycyrrhizin production is possible within a very short production period under controlled environments.

Environment, Controlled↗

A Rexx-controlled developing environment for implementing intuitive user interfaces (IUI).

In [our companion paper] intuitive user interfaces as well as a method for developing and programming such interfaces have been described. The present article will improve and simplify this mode of action. The main tool for this undertaking is the programming and script language Rexx. Using Rexx, all software components described in [the companion paper] are linked to form a developing environment, which acts like an integrated software package. Moreover, with the aid of Rexx, source-code and data structure generation is greatly extended, further decreasing the expenditure of programming intuitive user interfaces. This paper first gives a brief introduction to Rexx. A description of the Rexx-controlled developing environment then follows. Finally, there are elucidated the details of the question of how each single software component is linked to the environment using Rexx.

Computer Systems↗

Effect of heat shielding on convective and evaporative heat losses and on radiant heat transfer in the premature infant.

Ten premature infants nursed on servocontrolled radiant warmer beds were studied in three environments designed to alter one or more factors affecting heat transfer (convection, evaporation, and radiation). In the control environment, infants were nursed supine on an open warmer bed. The second environment (walled chamber) was designed to reduce convection and evaporation by placing plastic walls circumferentially around the bed. In the third environment convection and evaporation were minimized by covering infants with a plastic blanket. Air turbulence, insensible water loss, and radiant warmer power were measured in each environment. There was a significant reduction in mean air velocity in the walled chamber and under the plastic blanket when compared to the control environment. A parallel decrease in insensible water loss occurred. In contrast, radiant power demand was the same for control and walled environments, but decreased significantly when infants were covered by the plastic blanket. This study suggests that convection is an important factor influencing evaporation in neonates nursed under radiant warmers. The thin plastic blanket was the most effective shield, significantly reducing radiant power demand.

Bedding and Linens↗

Tissue-engineered vessel strengthens quickly under physiological deformation: application of a new perfusion bioreactor with machine vision.

In order to develop a patent tissue-engineered blood vessel that grossly resembles native tissue, required culture times in most studies exceed 8 weeks. For the sake of shortening the maturation period of the constructs, we have used deformation as the basic index for mechanical environment control. A new bioreactor with a machine vision identifier was developed to accurately control the deformation of the construct during the perfusion process. Two groups of seeded constructs (n = 4 per group) were investigated in this study, with one group stimulated by a cyclic deformation of 10% and the other by a pulsatile pressure that gradually increased to 120 mm Hg (the control group). After 21 days of culture, the mechanical properties of the constructs were examined. The average burst strength and suture retention strength in the two groups were significantly different (t test, p < 0.05). For the experimental group, the average burst strength and suture retention strength were higher than those of the control group, by 31.6 and 23.4%, respectively. Specifically, the average burst strength of the constructs reached 1,402 mm Hg (close to that of the native vessel, i.e. 1,680 mm Hg) within a relatively short period of 21 days. In conclusion, deformation is an observable, controllable and very valuable index for mechanical environment control in vascular tissue engineering. It makes the control of mechanical stimuli more essential and experiments more comparable.

Animals↗

Physiological responses of firefighters wearing level 3 chemical protective suits while working in controlled hot environments.

Firefighters in Queensland are exposed to hot, humid weather conditions that contribute to the overall workload encountered during emergency operations. Responding to certain hazardous material incidents requires firefighters to wear fully encapsulated chemical protective suits for a maximum period of 20 minutes. The nature of these suits, combined with workload and environmental conditions, poses a potential heat stress problem for firefighters. This study evaluates the heat-induced physiological responses of firefighters while wearing fully encapsulated chemical protective suits in a series of controlled thermal environments. Heart rate, body (aural) temperature, blood pressure, fluid loss, and a rating of perceived exertion were measured to evaluate the effect of increasing ambient air temperature during the performance of standard tasks. The results of the study indicated that the significant increase in heart rate, body temperature, and blood pressure was directly related to the increase in air temperature. The research indicates that the recommended suit wearing time of 20 minutes provided adequate physiological protection under the research conditions.

Adult↗

Military blood banking: blood transfusion aboard a Naval hospital ship receiving multiple casualties in a combat zone, a controlled medical environment.

The materials, methods, and policies used in the Blood Transfusion Service aboard the USS Sanctuary (AH-17) during military operations off South Vietnam to transfuse multiple casualties are outlined. Materials and methods common to any blood bank were used with some modification to meet specific requirements. During the period 10 April 1967 to 1 May 1971, approximately 32,000 units of blood were recieved, and over 2,890 severely injured patients were transfused. The policies and techniques used enabled efficient and safe management of blood transfusion for these patients. These methods should be applicable in solving some of the problems which arises as a result of combat operations and civil disasters. A controlled medical environment is described.

Adolescent↗

Hourly and seasonal variation in photosynthesis and stomatal conductance of soybean grown at future CO(2) and ozone concentrations for 3 years under fully open-air field conditions.

It is anticipated that enrichment of the atmosphere with CO(2) will increase photosynthetic carbon assimilation in C3 plants. Analysis of controlled environment studies conducted to date indicates that plant growth at concentrations of carbon dioxide ([CO(2)]) anticipated for 2050 ( approximately 550 micromol mol(-1)) will stimulate leaf photosynthetic carbon assimilation (A) by 20 to 40%. Simultaneously, concentrations of tropospheric ozone ([O(3)]) are expected to increase by 2050, and growth in controlled environments at elevated [O(3)] significantly reduces A. However, the simultaneous effects of both increases on a major crop under open-air conditions have never been tested. Over three consecutive growing seasons > 4700 individual measurements of A, photosynthetic electron transport (J(PSII)) and stomatal conductance (g(s)) were measured on Glycine max (L.) Merr. (soybean). Experimental treatments used free-air gas concentration enrichment (FACE) technology in a fully replicated, factorial complete block design. The mean A in the control plots was 14.5 micromol m(-2) s(-1). At elevated [CO(2)], mean A was 24% higher and the treatment effect was statistically significant on 80% of days. There was a strong positive correlation between daytime maximum temperatures and mean daily integrated A at elevated [CO(2)], which accounted for much of the variation in CO(2) effect among days. The effect of elevated [CO(2)] on photosynthesis also tended to be greater under water stress conditions. The elevated [O(3)] treatment had no statistically significant effect on mean A, g(s) or J(PSII) on newly expanded leaves. Combined elevation of [CO(2)] and [O(3)] resulted in a slightly smaller increase in average A than when [CO(2)] alone was elevated, and was significantly greater than the control on 67% of days. Thus, the change in atmospheric composition predicted for the middle of this century will, based on the results of a 3 year open-air field experiment, have smaller effects on photosynthesis, g(s) and whole chain electron transport through photosystem II than predicted by the substantial literature on relevant controlled environment studies on soybean and likely most other C3 plants.

Carbon Dioxide↗

The effects of disorientation on visual landmark control of head direction cell orientation.

Head direction (HD) and place cells were recorded in rats that had previously exhibited significant acquisition deficits on a radial arm maze task following disorientation treatment. In this study we determined whether this behavioral impairment was associated with a lack of landmark stimulus control over the preferred orientations of HD and place cells. Neurons were recorded as animals retrieved food pellets in a cylindrical apparatus containing a single cue card. Some of these HD cells were also recorded while animals explored an eight-arm radial maze in a similar cue-controlled environment. The stimulus control of the landmarks in each environment was assessed by rotating the landmark and examining the subsequent preferred orientations of HD and place cells. Animals underwent disorientation treatment before and after each recording session. Despite this disorientation, rotation of the cue card in the cylindrical apparatus resulted in a corresponding shift in the preferred orientations of HD and place cells in 13 of 15 and 7 of 7 recording sessions, respectively. On the radial arm maze, rotation of the landmark cue was associated with a corresponding shift in the HD cell's preferred orientation in 7 of 9 sessions. These results suggest that a visual landmark's stimulus control may not require a learned association between that landmark and an animal's stable experience in an environment. Furthermore, instability in the HD cell system is unlikely to account for the impaired performance of the disoriented animals in the radial arm maze. Rather, these impairments may be due to the animal's inability to utilize stable representations of the environment provided by HD and place cells.

Animals↗

Environmental modification of yield and nutrient composition of 'Waldmann's Green' leaf lettuce.

Leaf number, dry weight, and nutrient composition of Lactuca sativa L. cv. Waldmann's Green leaves were compared following 9 days of treatment in a controlled environment room under various combinations of photosynthetic photon flux (PPF:350 vs 800 micromoles m-2 s-1), atmospheric CO2 level (ambient vs 1500 micromoles mol-1), and single-strength (1X:15 mM) vs double-strength (2X:30 mM) nitrogen (N) as NO3- alone or as NH4(+) + NO3- (1:5 molar ratio). CO2 enrichment greatly enhanced leaf number under all PPF and N conditions, but increased leaf dry weight only at high PPF. Conditions favoring high photosynthesis enhanced leaf starch content 3-fold, and protein content increased as much as 64% with 2X NH4(+)+NO3-. Free sugar content was 6 to 9% of leaf dry weight for all treatment combinations, while fat was 1.5 to 3.5%. Ash content varied from 15 to 20% of leaf dry weight. Modified controlled environments can be used to enhance the nutritional content as well as the yield of crops to be used for life support in space-deployed, self-sustaining human habitats. Leaf lettuce is a useful model crop for demonstrating the potential of nutritional value added by environmental manipulation.

Biomass↗

Putting fear in its place: remapping of hippocampal place cells during fear conditioning.

We recorded hippocampal place cells in two spatial environments: a training environment in which rats underwent fear conditioning and a neutral control environment. Fear conditioning caused many place cells to alter (or remap) their preferred firing locations in the training environment, whereas most cells remained stable in the control environment. This finding indicates that aversive reinforcement can induce place cell remapping even when the environment itself remains unchanged. Furthermore, contextual fear conditioning caused significantly more remapping of place cells than auditory fear conditioning, suggesting that place cell remapping was related to the rat's learned fear of the environment. These results suggest that one possible function of place cell remapping may be to generate new spatial representations of a single environment, which could help the animal to discriminate among different motivational contexts within that environment.

Animals↗

A computer-controlled maze environment for testing visual memory in the rat.

A computer-controlled version of a Y-maze was developed to allow automated testing of rats' learning and memory with visual stimuli. Each of the 3 arms terminated with 2 adjacent monochromatic screens, 43 cm from the maze centre, providing a total stimulus area 47 cm wide by 18.5 cm high. The displays were abstract patterns extending across 2 screens, generated by algorithms which provided a large pool of discriminable patterns. The patterns used were of 2 general classes: Scenes (internally complex patterns with varying numbers of foreground shapes distributed across contrasted backgrounds) and Objects (internally homogeneous single figures, confined to the central part of the display). They could be stationary or have oscillatory movement. Subjects' location in the maze was monitored by infrared beam photodetectors; approach to correct patterns was rewarded with food. Pigmented rats of the Hooded Lister and Dark Agouti strains were tested. All could acquire 2-pair concurrent visual discriminations comprising 2 positive and 2 negative patterns, either Scenes or Objects; most could acquire 4-pair discriminations. Dark Agouti rats generally performed better than Hooded Listers. A novel training procedure using one positive and many negative patterns resulted in rapid learning of novel discriminations with either moving or non-moving patterns. The apparatus is an effective environment for visual learning by rats, suitable for a wide range of tasks in neuropsychology and psychopharmacology.

Animals↗

Efficacy of prophylactic ondansetron in a patient-controlled analgesia environment.

We conducted a prospective, randomized, double-blind, placebo-controlled trial to examine the efficacy of prophylactic ondansetron on post-operative nausea and vomiting (PONV) during opioid patient-controlled analgesia (PCA). In total, 374 patients using opioid PCA, but otherwise considered to be low risk for PONV, were randomly allocated to ondansetron (4 mg given intravenously and 16 mg added into the PCA pump) or saline (control group). PONV was evaluated in terms of nausea graded on a visual analogue scale, and the number of patients who experienced emetic episodes or needed rescue anti-emetics in the 48-h post-operative period. Patient satisfaction for PCA was scored at the end of the evaluation period. The only difference between the two groups was the higher number of headaches in the ondansetron group. In patients using opioid PCA, but with no other high risk factors for PONV, prophylactic ondansetron does not have any clinical benefit.

Aged↗